Devices responsive to linear acceleration perform essential sensing functions in a wide variety of systems. As performance requirements and available technology have advanced, the demand has increased for sensors characterized by much improved sensitivity, stability, accuracy, linearity of response, reliability and ruggedness, in addition to fast reaction time, minimum cross-coupling, small size, and low cost. Implicit in the stability, sensitivity and linearity requirements is a requirement that precision be maintained over a wide temperature range. The present state of the art is such that it has been difficult to achieve improvements in all of the foregoing characteristics simultaneously, or, in some instances, even to achieve improvement in one characteristic without adversely affecting another. Nevertheless, requirements exist, particularly in aircraft navigation and missile guidance systems, for an acceleration sensor with superior performance in all the noted areas.
A major error source in known accelerometers is bias instability, which results unless the mechanical null of the suspension system and the electrical null of the pickoff system remain coincident.